Reciprocatory impact hand tool



Sept. 22, 1959 R. M. TURNER RECIPROCATORY IMPACT HAND TOOL Filed April 18, 1958 United States Patent@ RECIPRQCATORYIMPACTHAND "TOOL Ralph M. Turner, Washington, D.C.

Application Aprill,` 1958, Serial`No.729,275

4 Claims.` (Cl.'.81"52.3`5)

The invention relates to new and-useful' improvements in reciprocatory impact hand tools for drivinggnails and numerous-other similar operations, and in particular the invention relates toltoolsr ofe-thegeneral type-disclosed in raypatents No; 2,749,548, issued June-121956;;andzNo: 2,850;739.; issued September 9,'1958.`

`ltr-:said patents there are disclosedtools of thistype which arte-'adapted for attachment to -aconventional electricuhandrdrill.` for coverting the rotaryrnotiondhereofA into'a reciprocating movement withaa definite impact during each stroke. The present invention, however, concerns itself with a tool'lwhich embodiesgan electric motor ast. a-V component thereof, so that the tooly is a Vtselfycontained unit.` rather than an attachment.`

The principal object of the present invention is to substantially improve the arrangement of my earlier inventions, this being attained by the provision of a selfcontained tool which is very simple in construction, durable -and efficient in operation, and which utilizes a minimum number of working parts.

With the foregoingmore important object and features in view and such other objects and features as may become apparent as this specification proceeds, the present invention will be understood from the following description taken in conjunction with the accompanying drawing, wherein like characters of reference are used to designate like parts, and wherein:

Figure 1 is a side elevational View of the device, shown partly in section to reveal its construction;

Figure 2 is a fragmentary vertical sectional view, taken substantially in the plane of the line 2 2 in Figure l;

Figure 3 is -a fragmentary horizontal sectional view, ta'ken `substantially in the plane of the line 3--3 in Figure l; and

Figure 4 is a sectional detail, taken substantially in the plane of the line 4-4 in Figure l.

Referring now to the accompanying drawing in detail, the improved tool is designated generally by the reference numeral and embodies in its construction an elongated, substantially tubular housing 11 which is provided at one end thereof with a downturned handle 12 and is also provided at the underside thereof with an inverted cup-shaped housing member 13 which is adapted to receive therein the upper end portion of a suitable electric motor 14. rThe motor 14 has the armature 1'5 thereof vertically disposed and is retained in the housing member 113 by a suitable clamp 1'6. The lower edge portion of the housing member 13 is preferably provided with one or more open slots (not shown) to facilitate proper clamping action of the motor therein by the clamp 16. The lower end of the handle 12 is provided with an upturned, apertured ear 17 for securing the same to the lower portion of the motor .116 by a suitable bolt or screw 118, as will be readily apparent.

A plunger 19 is reciprocable in the housing `11 against the action of a compression spring 20 which is also disposed in the housing in abutment with a screw-threaded plug .`21"provided in the end of the housing `adjacent the` handle 12; The plunger 19 isprovided with a diametrically reduced extension 19a ,which is reciprocablein, a retractable `work guide 22, slidably mounted in a screwthreadedjbushing 23 at the other end' of the housing 11.

The work engaging end of `the plunger` extension 19d is.- illustrated at 19b and the arrangement of `thework guide" 22' is the same as in my prior patent andco-pending application, both already identified. The work guide 22A is .urged outwardly bya compression spring 24 which is..

interposed between the workguide and a collar 25 secured to the plunger extension f19a.4

The housing y11 is provided intermediate its ends with a partition 26. having anV aperture therein toprovide a bearing for the plunger extension 19a, an oilsealj27 beingprovided in the opening of the partition to retain lubricant in the portion of thehousing which contains the reciprocabl'e plunger 19. A shock absorber,

spring'r28, weaker than the` spring20, is interposed between the,partiti`on 26 and the plunger 19, in accordance with` the teachings of my prior patent and co-pendingapplica tion.

The plunger 19` isreciprocated-by a cam 29 secured 29 is rotated by the motor 14, the plunger 19 will be? alternately retracted against the spring 2li and projected by the spring 20 upon disengagement of the cam from the follower 33, thus causing the end 19b of the plunger extension 419a to deliver a positive impact against the work' during each revolution of the cam.

In order to safeguard the motor 14 from harmful effects incident to the impacts delivered by the tool, the shaft 30 is not connected directly to the armature of the motor, but shock absorbing means -are provided for sueh a connection. These means comprise a pair of discs 34, 35, one of which is provided on the armature 1S while the other is secured to the lower end of the shaft 30. A shock absorbing disc 36 of rubber, or the like, is interposed between the discs 34, 35 and is operatively connected to the disc 34 by a set of driving pins 37. Similarly, the disc 35' is operatively connected to the disc 36 by a set of driving pins 38. Thus, the drive from the armature I15 to the shaft 30 is taken through the medium of the shock absorber disc 36 and transmission of impacts from the plunger i19 to the motor 14 is eliminated.

The armature '15 is provided with a diametrically reduced extension 15a which passes through the discs 36, 35 and is slidably and rotatably journalled in a suitable bore formed in the lower end portion of the shaft 30, thus assisting to retain the shaft 30 in alignment with t'ne armature; This extension (|1511), however, does not transmit any shock from the shaft 30 to the motor, since the shock is torsional rather than longitudinal and the extension 15a is rotatable in the bore of the shaft 30 so that no torsional shock can be transmitted thereby.

It is to be particularly noted that the cam 29 is disposed in the plane of the axis of reciprocation of the plunger 19 and actuates the plunger in a direct line,

without any lateral distortion or stresses being present,-

such as are involved when the cam is disposed at one side of the plunger.

While in the foregoing there has been described and show the preferred embodiment of the invention, var- Patented Sept. 22,VA 1959 The cam 29' is located in a recess 32. fo1'med ions modications may become apparent to those skilled in the art Ito which the invention relates. Accordingly, it is not desired to limit the invention to this disclosure, and various modications may be resorted to, such as may lie within the spirit and scope of the `appended claims.

What is claimed as new is: V1. In a reciprocatory impact tool, the combination of an elongated housing, a plunger reciprocable therein between projected and retracted posi-tions, resilient means in Vsaid housing for urging the plunger to its projected position, a motor carried by said housing and having an armature disposed at right angles to said plunger, a cam operatively connected to said armature and disposed in the plane of the axis of reciprocation of the plunger, follower means provided on the plunger and operatively engageable by said cam, whereby the plunger may be retracted against the action of said resilient means, and shock absorber means operatively connecting said cam to said armature.

2. The device as dened in claim 1 together with a handle provided on said housing and supportably connected to said motor.

3. In a reciprocatory impact tool, the combination of a substantially tubular housing, a downturned handle provided at one end thereof, an inverted cup-shaped housing member provided at the underside of the housing, an electric motor having its upper end portion secured in said housing member, the lower end portion of said motor being secured to said handle, said motor including an upwardly extending armature disposed perpendicularly to said housing, a recessed plunger reciprocable in the housing between projected and retracted positions, resilienty means provided in the housing for urging said plunger to its projected position, a shaft rotably journalled in said housing member and yaligned axially with said armature, shock absorber means operatively connecting said shaft to said armature, a cam provided on said shaft within the recess of said plunger and in -the plane of the axis of reciprocation of the plunger, and follower means provided on the plunger within lthe recess thereof and operatively engageable by said cam, whereby the plunger may be retracted against the action of Y said resilient means.

4. The device dened in claim 3 wherein said shock absorber means comprise a pair of discs secured to said armature and to said shaft, adisc of shock absorbing material interposed between Said pair of discs, and pins projecting from the respective discs in the pair into said disc of shock absorbing material, whereby to operatively connect the same together.

References Cited in the le of this patent UNITED STATES PATENTS 1,356,297 Lochner Oct. 19, 1920 1,464,824 Kollock et al Aug. 14, 1923 1,511,566 Kollock Oct. 14,v 1924 2,501,542 Sheldon Mar. 21, 1950 2,626,598 Tarwater Jan. 27, 1953 2,655,921 Haboush Oct. 20, 1953 FOREIGN PATENTS 506,743 Italy Dec. 24, 1954 810,498 Germany a i Aug. 9, 1951 

